Successful artificial insemination in Lemur fulvus mayottensis

Cryopreservation of lar gibbon semen collected by manual stimulation

We confirmed ejaculation as a result of manual stimulation in a lar gibbon, and attempted to cryopreserve the semen using TES-Tris-egg yolk-based (TTE) extender. After measuring the amount of semen (g), we first diluted the semen with TTE extender, and calculated sperm concentration (sperm/ml), total sperm count (sperm), and progressive sperm motility (%). Then, we cooled diluted semen slowly to 4 °C over 2 h, and added an equal volume of secondary extender containing glycerol over 30 min. Finally, we flash-froze the semen solution by plunging into liquid nitrogen. In addition, we freeze-thawed the solution to determine the recovery rate of the motile sperm. Collection of semen was successful on four of the five occasions. The median (min-max) quantity of ejaculate was 0.19 g (0.09-0.26 g), the median sperm concentration was 1.38 × 10(9) sperm/ml (1.20-1.53 × 10(9) sperm/ml), and the median total sperm count was 0.26 × 10(9) sperm (0.11-0.40 × 10(9) sperm). Moreover, the median sperm motility immediately after ejaculation was 65 % (60-75 %), the median sperm motility after freeze-thawing was 30 % (25-35 %), and the median recovery rate was 42.3 % (40.0-58.3 %). We were able to (1) collect semen from a lar gibbon by manual stimulation, (2) reveal andrological findings regarding semen characteristics, and (3) preserve the genetic resource using TTE cryopreservation.

Prevention of urethral blockage following semen collection in two species of lemur, Varecia variegata variegata and Lemur catta

Lemurs are a diverse group of primates comprised of five families, all of which are found only on Madagascar and the Comoro Islands. Of the 60 known species, 17 are endangered and 5 of these are considered critically endangered. The effects of inbreeding on population health and viability have been well described; though negative inbreeding effects can be ameliorated through the introduction of new genetic material. Introduction of new individuals into a population can be extremely challenging because of the highly social nature of lemurs. Semen collection in lemur species is notoriously challenging, as the ejaculate forms a coagulum. During normal breeding, the coagulum forms a copulatory plug in the female. However, this coagulum can present a life-threatening situation when retained in the urethra abnormally following electroejaculation. This study investigates the use of ascorbic acid in preventing urethral blockage in two lemur species during semen collection, demonstrates successful collection of semen by electroejaculation from two species of lemur during the breeding season, and discusses removal of urethral plugs subsequent to semen collection. Semen was collected successfully from all animals. Urethral plugs formed during each collection and were abnormally retained in 2/11 collections. Both plugs were successfully and immediately removed with the use of retropulsion through a urethral catheter. Although the results of this study are encouraging, more investigation is required to establish whether or not this procedure can be safely performed in the field.

Birth of offspring following artificial insemination in the common marmoset, Callithrix jacchus

The objective of the study was to develop a method for artificial insemination (AI) in the common marmoset, a New World primate species. For AI to be successful, sperm must be deposited at an appropriate site and time in the female reproductive tract, details of which are currently not available for Callitrichid species. Epididymal sperm were deposited in the cervix of 18 marmoset monkeys (Callithrix jacchus) around the time of expected ovulation using either 3, 2, or 1 inseminations. Six out of 18 females conceived, resulting in the first reported births following AI in this species. These pregnancies show that the presence of coagulum in the vagina and the stimulus of the female reproductive tract by natural mating are not essential for effective sperm transport in this species. Although 3 different timing regimes for sperm deposition relative to ovulation were employed, no protocol was demonstrably better than the others in terms of number of conceptions. The proportions of motile, live, and morphologically normal sperm in the suspensions used for AI were comparable with published values for ejaculates from fertile male macaques. These preliminary results indicate that births are possible following AI in marmosets: the technique could be used to aid effective genetic management of the species and possibly to facilitate captive breeding of endangered Callitrichids.

Artificial insemination in Callithrix jacchus using fresh or cryopreserved sperm

Assisted reproductive techniques are needed urgently to facilitate the captive breeding of many New World primate species which are endangered in the wild and to assist the effective genetic management of small colonies. A protocol was devised for artificial insemination in the common marmoset, Callithrix jacchus, using ejaculated sperm obtained by vaginal washing after copulation. A double insemination protocol was employed, with the first insemination taking place the day before ovulation was expected to occur and the second 48 h later. All six females inseminated with fresh ejaculated sperm became pregnant, delivering a total of 16 offspring at term. The gestation lengths and litter sizes were not statistically different from those observed in pregnancies following natural mating. The insemination protocol was adapted for use with cryopreserved ejaculated sperm by including an additional insemination on the day of expected ovulation, to take into account differences in the capacitation time of frozen-thawed sperm compared to fresh sperm. Three out of six females inseminated according to this triple insemination schedule, conceived, although one female subsequently resorbed twin foetuses approximately 100 days later. The remaining two pregnant females delivered four babies at term, one singleton and one set of triplets. In the final group, six females were inseminated with low doses of cryopreserved epididymal sperm using the same triple insemination protocol used for frozen-thawed ejaculated sperm. One female conceived, delivering triplets.